Integrated electronic circuits generally comprise active components, such as transistors, produced on the surface of a semiconductor substrate. They also comprise layers of electrically insulating materials superposed on top of the surface of the substrate, within which layers metal tracks, constituting electrical connections between the active elements, are placed.
Furthermore, certain circuits currently produced include passive components, such as resistors, inductors or capacitors that are also placed within the layers of insulating materials. Typically, these components are produced in a form in which they are integrated into the circuit; they are produced during the formation of the superposed layers of insulating materials, by suitable deposition of specific materials.
However, certain passive components, particularly capacitors of high capacitance, have a large footprint because of their large size. It is then difficult to make the placing of these components within the layers of insulating materials compatible with the placement of the electrical connection tracks. To take an example, a capacitor may have a length of up to several hundred microns, depending on its capacitance. This footprint requires the size of the circuit substrate to be increased, so as to be able to place all the components and all the necessary connection tracks within the layers of insulating materials that cover the substrate. This therefore results in an increase in cost of the integrated circuit, this increase being particularly burdensome in respect of large-scale diffusion in such circuits.
Accordingly, a need exist to overcome the shortcomings and drawbacks of the prior art with the size reduction of capacitors in integrated electronic circuits.